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Is X divisible by 15????

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by force5 » Wed Mar 23, 2011 11:18 am
IMO-C

stmnt 1 - x will be multiples of 10 however 10 is not divisible by 15 where as 30 is

stmnt 2 - if x^2 is a multiple of 30 then x can be anything.

combining... we get multiples of 30..
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by clock60 » Wed Mar 23, 2011 11:20 am
here i got B
x is divisible by 15 if it is divisible by 3 and 5
(1) says that x is divisible by 10 it means that x is divisible by 2 and 5, but as no info about 3 insuff
(say for example 10 and 30)
(2) says that x contain at least 2,3, 5 as factors, so it is divisible by 15 suff
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by Night reader » Wed Mar 23, 2011 11:38 am
Is x/15=i {i is integer}?
division by 15 assumes division by 3 and division by 5

st(1) if x is divided by 10, then x contains 2 and 5 as prime factors, BUT we are not sure about 3 Not Sufficient;
st(2) if x^2 is divided by 30. Since factors of 30 are 2*3*5 and none are squared numbers - i.e. number^2, we deduce that x alone is divided by 30. Sufficient, as x contains both 3 and 5.

IOM B

explanation st(2) let 'a' be integer --> a*a/(2*3*5), a should be divisible by 2,3 and 5
AIM GMAT wrote:Is X divisible by 15?

1.When X is divided by 10, the result is an integer.
2. X^2 is a multiple of 30.
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by manpsingh87 » Wed Mar 23, 2011 9:42 pm
AIM GMAT wrote:Is X divisible by 15?

1.When X is divided by 10, the result is an integer.
2. X^2 is a multiple of 30.
IMO both the statements are not sufficient to answer the question,

1) x is multiple of 10; so that means for different values of x different result are possible; hence 1) alone is not sufficient.

2) as x^2 is a multiple of 30, now here important thing to consider is nothing is said about x whether its an integer or non-integer, so we have to consider non integral cases here as well. for example if x is sqrt(30) then x^2=30 which is a multiple of 30, but x=sqrt(30) is not divisible by 15; if x is integer then, x would definitely be divisible by 15. as different cases are possible in case of statement 2, hence statement 2 alone is also not sufficient to answer the question.

Even if we combine statement 1 and 2 then also we won't be able to yield any unique solution.

hence both are not sufficient. hence E
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by Night reader » Thu Mar 24, 2011 1:46 am
Combining all previous inputs

Combined st(1&2): x is divided by 10 is an integer and x^2 is a multiple of 30 must be sufficient, as both statements set cut-off on x as integer and the number having factors 2,3,5.

answer has to be C
manpsingh87 wrote:
AIM GMAT wrote:Is X divisible by 15?

1.When X is divided by 10, the result is an integer.
2. X^2 is a multiple of 30.
IMO both the statements are not sufficient to answer the question,

1) x is multiple of 10; so that means for different values of x different result are possible; hence 1) alone is not sufficient.

2) as x^2 is a multiple of 30, now here important thing to consider is nothing is said about x whether its an integer or non-integer, so we have to consider non integral cases here as well. for example if x is sqrt(30) then x^2=30 which is a multiple of 30, but x=sqrt(30) is not divisible by 15; if x is integer then, x would definitely be divisible by 15. as different cases are possible in case of statement 2, hence statement 2 alone is also not sufficient to answer the question.

Even if we combine statement 1 and 2 then also we won't be able to yield any unique solution.

hence both are not sufficient. hence E
My knowledge frontiers came to evolve the GMATPill's methods - the credited study means to boost the Verbal competence. I really like their videos, especially for RC, CR and SC. You do check their study methods at https://www.gmatpill.com
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by manpsingh87 » Thu Mar 24, 2011 2:26 am
Night reader wrote:Combining all previous inputs

Combined st(1&2): x is divided by 10 is an integer and x^2 is a multiple of 30 must be sufficient, as both statements set cut-off on x as integer and the number having factors 2,3,5.

answer has to be C
manpsingh87 wrote:
AIM GMAT wrote:Is X divisible by 15?

1.When X is divided by 10, the result is an integer.
2. X^2 is a multiple of 30.
IMO both the statements are not sufficient to answer the question,

1) x is multiple of 10; so that means for different values of x different result are possible; hence 1) alone is not sufficient.

2) as x^2 is a multiple of 30, now here important thing to consider is nothing is said about x whether its an integer or non-integer, so we have to consider non integral cases here as well. for example if x is sqrt(30) then x^2=30 which is a multiple of 30, but x=sqrt(30) is not divisible by 15; if x is integer then, x would definitely be divisible by 15. as different cases are possible in case of statement 2, hence statement 2 alone is also not sufficient to answer the question.

Even if we combine statement 1 and 2 then also we won't be able to yield any unique solution.

hence both are not sufficient. hence E
consider x as 20 sqrt(5);it is divisible by 10 but its not an integer..!!!
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by Geva@EconomistGMAT » Thu Mar 24, 2011 2:43 am
manpsingh87 wrote:
Night reader wrote:Combining all previous inputs

Combined st(1&2): x is divided by 10 is an integer and x^2 is a multiple of 30 must be sufficient, as both statements set cut-off on x as integer and the number having factors 2,3,5.

answer has to be C
manpsingh87 wrote:
AIM GMAT wrote:Is X divisible by 15?

1.When X is divided by 10, the result is an integer.
2. X^2 is a multiple of 30.
IMO both the statements are not sufficient to answer the question,

1) x is multiple of 10; so that means for different values of x different result are possible; hence 1) alone is not sufficient.

2) as x^2 is a multiple of 30, now here important thing to consider is nothing is said about x whether its an integer or non-integer, so we have to consider non integral cases here as well. for example if x is sqrt(30) then x^2=30 which is a multiple of 30, but x=sqrt(30) is not divisible by 15; if x is integer then, x would definitely be divisible by 15. as different cases are possible in case of statement 2, hence statement 2 alone is also not sufficient to answer the question.

Even if we combine statement 1 and 2 then also we won't be able to yield any unique solution.

hence both are not sufficient. hence E
consider x as 20 sqrt(5);it is divisible by 10 but its not an integer..!!!
x=20*sqrt(5) does not satisfy stat. (1), since 20*sqrt5 / 10 = 2*sqrt(5) is not an integer.

The real translation of stat. (1) is x/10 = int, which would make x equal 10*integer - which would in turn make x an integer.
Answer is indeed C.
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